Back End - Back end ratings seem to confuse bowlers. A ball's "back end" is the angle or degree of hook at the breakpoint. The confusion comes from the term "back end." The ball may break at 20 feet, 30 feet, or 40 feet. That doesn't matter. What you are evaluating is not how much it hooks, but more WHEN it hooks; i.e. the ability of a ball to make a turn back to the pocket. Since there is the potential for balls to have more and less back end, BTM needed a benchmark that would leave room in both directions. Again, the Danger Zone was selected and it was assigned a back end rating of 10. Remember that these are comparisons so 10 doesn't mean anything by itself. It would mean for comparisons that it is stronger than balls rated 9.5 and lower and it would be weaker than balls rated at 10.5 and higher.

Ball Track - (1) the area of the lane where most balls are thrown; (2) the area on a ball here the ball rolls; most balls will show scratches and wear in this area after several games.

Break Point - The portion on the lane where the thrown ball begins to hook back to the pocket. Finding the proper breakpoint (called "breakpoint management") is critical to the modern game. A ball that hooks too early or one that hooks too late will make it very difficult for a player to be consistent. Breakpoints can be adjusted by making changes in alignment, target, ball, ball surface and ball speed.

Bonanza Ball - A Bonanza Ball is basically a ball that is labeled Bonanza instead of having the manufacturers name and make of the particular ball on it. The ball has the indentical look, coverstock, color's, weight blocks and technical specifications. Warning: In some cases, Bonanza Labeled balls are not recognized by USBC in tournement play. Check with your local USBC governing office for more details.

Carry Down - The oil conditioner on the lane does not soak into the boards, it sits on top. As balls are thrown, the oil is subtly moved...it might be pushed left and right, or, it might be moved farther down the lane (carried down). Usually, but not always, a house with a lot of carrydown will not allow a ball to hook as much on the back ends and scores will be lower. In some houses and oil patterns, the initial pattern is too much over/under and carry increases as the carrydown effect takes place.

Coverstock - The material that makes up the outer shell of the ball; the hardness, texture, and shine of a bowling ball. It is generally defined as Aggressive, meaning it is made of a high friction material that is prone to large hook or flip when it encounters dry boards; or, Medium which displays less tendency to hook; and, Mild/Mellow which is the lowest friction material and the least sensitive to dry lanes.

Differential - It is the difference between the lowest and highest RGs. You compute the high and subtract the low from that and you have the differential. There is no minimum for differential. What differential tells you: RG Differential is an indicator of track flare POTENTIAL in a bowling ball. Differentials in the .01s to .02s would mean that a ball has a lower track flare potential, .03s to .04s would be the medium range for track flare potential, and the .05s to .080 would indicate a high track flare potential. These ranges above are not based on cardinal rules. They are BTM in-house rules of thumb because there are no published guidelines. Also, differential is a guide to the internal versatility of a ball. It can indicate just how much of a length adjustment can be made through drilling. A low differential will allow for only a modest variance in length (from shortest drilling to longest) which may translate into as little as a foot or two. An extremely high differential may translate into a length window in the neighborhood of eight feet.

Dry Lane Ball - A ball that for you and your game performs better on dry lanes than on more heavily conditioned lanes; you can sometimes achieve the result by polishing a ball to make it shinier so that it skids more before hooking.

Dry Lane - A lane that has less conditioner than normal for your game; usually means earlier and more hook.

Entry Angle - The angle relative to the pocket that the balls enters the pocket. As a rule, increased angle means increased strikes (hence the preference for a ball that hooks a lot or for clean back ends.)

Finger Weight - The drilling of a ball so that the finger holes are closer to the ball's label than is the thumbhole; it is a form of positive weight.

Finish ( As applied to the ball reaction ) - The final "drive" the ball makes toward the pocket. .. a ball that fails to finish comes up short and leaves (at best) a half-ten, or a bucket. Can be the result of a poorly released shot, or from backends afflicted with "carrydown".

Finish ( As applied to the ball surface ) - The amount of shine/gloss on the ball. As a general rule, balls that are heavily polished and shiny tend to go farther down the lane before beginning to hook; conversely, balls with a lot of surface (from sanding perhaps) tend to begin to hook much earlier.

Flare - The migration of the ball track from the bowler's initial axis, the axis upon release, to the final axis, the axis at the moment of impact with the pins.

Hook - A ball that breaks rather sharply toward the pocket, as opposed to a curve.

Length - Length is an evaluation of how far a ball will travel before it begins to hook. Length does not include skid produced by lane conditioner, additional fine sanding, or the use of "liquid sandpaper" polishes. BTM uses the Danger Zone as a control ball and it has an assigned length value of 2 on a scale of 10.

Radius of Gyration (RG)-Identifies how fast a ball begins to rotate once it leaves the bowler's hand.

Reactive Resin - A polymer that is a cousin to traditional urethane; used as the coverstock on most modern balls; it is generally a surface that grabs the lane sooner, resulting in more and earlier hook than other coverstock surfaces. They can feel "tacky/sticky" when warm. They tend to "react" much more to differing lane surfaces, hooking more on drier lanes and skidding more in oil.

Roll Out - A ball that loses its side rotation before hitting the pins; the hook action stops at that point and the ball straightens out; generally undesirable; see also "hookout" and "hook and set".

Rotation - The spin given to the ball that creates both the break and action.

Short Oil - Also known as "limited distance dressing/LDD". A condition in which oil is applied to the front 24 feet or less of the lane, with the remainder dry. Can be very high scoring.

Snap - Usually refers to the ability of a ball to "go long" and then make a violent turn back to the pocket. A bowler that has a "skid-snap" reacting ball will create large entry angles, but at some expense of accuracy. See also "arc".

Spare Ball - A ball used by players primarily for covering single pin spares. Typically, a "spare" ball will be a low hooking polyester ball that the player can throw straight at the pin, hopefully taking any lane condition factors out of the spare shooting process; also, it is the name of a ball made by STORM Products.

TopWeight - Drilling of a ball so that there is more weight above the label than there is below; it is considered a positive weight. See "bottom weight".

Track - Either "ball track", which is the area on the surface of the ball upon which the ball rotates as it goes down the lane; or. the area of a lane where most players in that center throw their normal strike line.

Turn- The motion of the hand and wrist that imparts rotation to the ball at release.

Urethane - A plastic blend that is normally softer and more porous than polyester; coverstock favorite until the advent of reactive resin.

Weight Block - The interior portion of a ball that adds extra weight to it to bring the overall gross weight higher. Knowledge of the location of the weight block is used to create balls with differing positive and negative weight distributions.

X-Out, 2nd's, Blem's - Manufacturers release their high performance bowling balls under the X-Blem, X-Out or Second label when small non-performance issues occur. The core and coverstock combinations on these bowling balls are identical to the first line bowling balls.

A bolwing ball is labeled an X-Blem, X-Out, or Second for any one of the following reasons:

Color pigmentation

Small pitting caused by air bubbles.

Unique pin placement, top weight, or mass bias marking location.

Labels are engraved in unusual places or may have the wrong logos engraved on ball.

Swirl patterns of the ball are not consistent, which may effect the color (look) of the ball greatly.

Engravings such as the serial numbers, cg location markers or logos may be stamped on the ball more than once.

These differences do not effect the performance of the bowling ball or the ability to drill the bowling ball. Therefore allowing bowlers to purchase top of the line bowling equipment at a fraction of the cost.